According to "Fantastic Beasts and Where to Find Them", although the creation of a Basilisk is relatively simple, it's not something that most witches or wizards would contemplate due to the fact that it's...
- Illegal
- Stupid
The quote from the book is that
"The creation of Basilisks has been illegal since medieval times"
and that any attempt to breed one will likely result in a visit from the
"Department for the Regulation and Control of Magical Creatures"
On top of that,
[Since] Basilisks are uncontrollable except by Parselmouths, they are as dangerous to most Dark wizards as to anybody else, and there have been no recorded sightings of Basilisks in Britain for at least four hundred years.